diff --git a/.tmux.conf b/.tmux.conf
index cd1830a..97c9222 100644
--- a/.tmux.conf
+++ b/.tmux.conf
@@ -156,17 +156,17 @@ run 'cut -c3- ~/.tmux.conf | sh -s apply_configuration'
 #   tmux_conf_theme=${tmux_conf_theme:-default}
 #   case "${tmux_conf_theme}" in
 #     powerline|powerline_patched_font)
-#       left_separator=''
-#       left_separator_black=''
-#       right_separator=''
-#       right_separator_black=''
+#       left_separator=${tmux_conf_theme_left_separator-}
+#       left_separator_black=${tmux_conf_theme_left_separator_black-}
+#       right_separator=${tmux_conf_theme_right_separator-}
+#       right_separator_black=${tmux_conf_theme_right_separator_black-}
 #       session_symbol=''
 #       ;;
 #     ""|default)
-#       left_separator='|'
-#       left_separator_black=''
-#       right_separator='|'
-#       right_separator_black=''
+#       left_separator=${tmux_conf_theme_left_separator-|}
+#       left_separator_black=${tmux_conf_theme_left_separator_black-}
+#       right_separator=${tmux_conf_theme_right_separator-|}
+#       right_separator_black=${tmux_conf_theme_right_separator_black-}
 #       ;;
 #   esac
 #
@@ -177,9 +177,16 @@ run 'cut -c3- ~/.tmux.conf | sh -s apply_configuration'
 #       tmux_conf_theme_pane_border_fg=${tmux_conf_theme_pane_border_fg:-colour238}               # light gray
 #       tmux_conf_theme_pane_active_border_fg=${tmux_conf_theme_pane_active_border_fg:-colour39}  # light blue
 #
-#       tmux set -g pane-border-style fg=$tmux_conf_theme_pane_border_fg \; set -g pane-active-border-style fg=$tmux_conf_theme_pane_active_border_fg
-#       #uncomment for fat borders
-#       #tmux set -ga pane-border-style bg=$tmux_conf_theme_pane_border_fg \; set -ga pane-active-border-style bg=$tmux_conf_theme_pane_active_border_fg
+#       # if tmux_conf_theme_pane_border_bg is not defined
+#       if [ x"${tmux_conf_theme_pane_border_bg+x}" = x"" ] ; then
+#         tmux set -g pane-border-style fg=$tmux_conf_theme_pane_border_fg \; set -g pane-active-border-style fg=$tmux_conf_theme_pane_active_border_fg
+#         #uncomment for fat borders
+#         #tmux set -ga pane-border-style bg=$tmux_conf_theme_pane_border_fg \; set -ga pane-active-border-style bg=$tmux_conf_theme_pane_active_border_fg
+#       else
+#         tmux_conf_theme_pane_border_bg=${tmux_conf_theme_pane_border_bg:-default}
+#         tmux_conf_theme_pane_active_border_bg=${tmux_conf_theme_pane_active_border_bg:-$tmux_conf_theme_pane_border_bg}
+#         tmux set -g pane-border-style fg=$tmux_conf_theme_pane_border_fg,bg=$tmux_conf_theme_pane_border_bg \; set -g pane-active-border-style fg=$tmux_conf_theme_pane_active_border_fg,bg=$tmux_conf_theme_pane_active_border_bg
+#       fi
 #
 #       tmux_conf_theme_display_panes_active_colour=${tmux_conf_theme_display_panes_active_colour:-colour39}  # light blue
 #       tmux_conf_theme_display_panes_colour=${tmux_conf_theme_display_panes_colour:-colour39}                # light blue